The Border Gateway Protocol (BGP) allows an autonomous system (AS) to apply diverse local policies for selecting routes and propagating reachability information to other domains. However, BGP permits autonomous systems to have conflicting policies that can lead to routing instability.
Routing and connectivity in the Internet is largely governed by the dynamics and configuration of the Border Gateway Protocol. Network operators use BGP to route traffic between autonomous systems in the Internet, and to enforce complex peering policies with their customers, peers and providers. BGP is a policy and configuration intensive protocol that lends itself to the implementation of complicated topologies and connectivity. While there is much ado about BGP policy, most network operators use manual or scripting based techniques to manage BGP configuration and implement complex administrative policies. Recent studies have shown that nearly 95% of all new prefix advertisements in the Internet routing table can be attributed to mis-configuration.
BGP configuration is difficult to implement. BGP is a flexible, policy-based routing protocol where policies are implemented by complex configurations. Configuration is not based on policies, but on mechanisms. Configuration is often implemented in response to network events. Configuration grows over time as events happen. In order to specify a single policy, a large number of parameters must be adjusted.
Analysis and policy visualization of implemented BGP configuration enable service providers to move from checking of low-level configuration to extracting analyzable BGP level policy information across a multitude of BGP routers in order to validate consistency of policies and operator intent across distributed BGP configuration using a flexible, customizable analysis engine.
The name Infer refers to a Telcordia Technologies BGP configuration analysis toolkit. The Infer configuration analysis toolkit enables network operators to discover, analyze and diagnose their BGP configuration, policies and peering relationships. Infer analysis components include variations of Invariant, Best Current Practices (BCP), Statistical Variance and Dynamic analyses. A key feature of Infer is the ability to perform policy based analysis even in the absence of an articulation of high-level policy from the network operator. The Infer toolkit can interact with external data sources such as Internet Routing Registries and BGP monitors, and can enable operators to validate the consistency of policies and operator intent across distributed BGP configuration.
While there exist toolkits for analyzing BGP configurations, there is a need for a more accurate method which relies upon statistical variance of policies to control the BGP configuration.